Horton

Re: Broken defenses against dropping a partitioning column

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: pgsql-hackers@lists.postgresql.org, Manuel Rigger <rigger.manuel@gmail.com>
Date: 2019-07-19T18:14:03Z
Lists: pgsql-hackers

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I wrote:
> So I think we're probably stuck with the approach of adding new internal
> dependencies.  If we go that route, then our options for the released
> branches are (1) do nothing, or (2) back-patch the code that adds such
> dependencies, but without a catversion bump.  That would mean that only
> tables created after the next minor releases would have protection against
> this problem.  That's not ideal but maybe it's okay, considering that we
> haven't seen actual field reports of trouble of this kind.

Here's a proposed patch for that.  It's mostly pretty straightforward,
except I had to add some recursion defenses in findDependentObjects that
weren't there before.  But those seem like a good idea anyway to prevent
infinite recursion in case of bogus entries in pg_depend.

I also took the liberty of improving some related error messages that
I thought were unnecessarily vague and not up to project standards.

Per above, I'm envisioning applying this to HEAD and v12 with a catversion
bump, and to v11 and v10 with no catversion bump.

			regards, tom lane

Commits

  1. Make pg_upgrade's test.sh less chatty.

  2. Install dependencies to prevent dropping partition key columns.